Chain Exchange Kinetics in Diblock Copolymer Micelles in Ionic Liquids: The Role of χ
Chain Exchange Kinetics in Diblock Copolymer Micelles in Ionic Liquids: The Role of χ
复制标题
离子液体中二嵌段共聚物胶束的链交换动力学：χ 的作用
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
T. Lodge
中科院分区：
文献类型：
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作者：
Yuanchi Ma;T. Lodge
采用时间分辨小角中子散射（TR-SANS）方法研究了具有低临界胶束化温度（LCMT）相行为的嵌段共聚物胶束的链交换动力学。三个几乎相同的同位素取代的聚（甲基丙烯酸甲酯）-嵌段-聚（甲基丙烯酸正丁酯）（PMMA-b-PnBMA）二嵌段对用于室温离子液体1-乙基-3-甲基咪唑鎓双（三氟甲基磺酰基）酰亚胺和1-丁基-3-甲基咪唑鎓双（三氟甲基磺酰基）酰亚胺的混合物中。在这种情况下，h-PnBMA和d9-PnBMA嵌段形成胶束核。结果是一致的，与以前的测量在其他系统中，在障碍链提取规模与核心块长度呈线性关系。通过改变混合物中两种同系溶剂的比例，系统地改变芯嵌段和溶剂之间的χ值。结果表明，溶剂选择性对链交换速率有显著的影响，这与B的理论预测相符。
Chain exchange kinetics of diblock copolymer micelles with lower critical micellization temperature (LCMT) phase behavior were investigated using time-resolved small-angle neutron scattering (TR-SANS). Three nearly identical isotopically substituted pairs of poly(methyl methacrylate)-block-poly(n-butyl methacrylate) (PMMA-b-PnBMA) diblocks were used in mixtures of the room temperature ionic liquids 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. In this case, the h-PnBMA and d9-PnBMA blocks form the micellar cores. The results are consistent with previous measurements in other systems, in that the barrier to chain extraction scales linearly with the core block length. By varying the ratio of the two homologous solvents in the mixture, the value of χ between the core block and the solvent is varied systematically. The results show that the solvent selectivity has a remarkable effect on the chain exchange rate, as anticipated b...